Blends of dibenzoate plasticizers

ABSTRACT

Plasticizer blends comprise a triblend of diethylene glycol dibenzoate, dipropylene glycol dibenzoate, and 1,2-propylene glycol dibenzoate, in specified ratios, useful in combination with a multitude of thermoplastic polymers, thermosetting polymers, and elastomeric polymers and numerous applications, including but not limited to plastisols, adhesives, sealants, caulks, architectural coatings, industrial coatings, OEM coatings, inks, overprint varnishes, polishes, and the like. The advantages rendered by the use of the triblend depend on the type of polymer and application in which it is utilized and include among other advantages higher solvating power and lower processing time, low VOC&#39;s, reduced plasticizer freeze point, improved gelation and fusion characteristics, higher tensile strength, superior stain and extraction resistance, and improved rheology over traditional diblends of diethylene glycol dibenzoate and dipropylene glycol dibenzoate.

FIELD OF THE INVENTION

The present invention relates to a non-phthalate plasticizer triblendcomprising dibenzoate plasticizers, in specific proportions, all ofwhich are compatible with each other and can be utilized in a variety ofpolymer applications traditionally requiring plasticizers, including butnot limited to plastisols, adhesives, caulks, architectural coatings,industrial coatings, OEM coatings, inks, overprint varnishes, othercoatings, polishes and the like. The inventive plasticizer blendsimprove performance properties of the polymer, such as processabilityand stain and extraction resistance, among others. The invention is alsodirected to polymeric compositions comprising the plasticizer triblend,such as plastisols and adhesives.

BACKGROUND OF THE INVENTION

Plasticizers, as polymer additives, are established main line additivesand have been known for more than a century. Most high volumeplasticizers have been developed in the last seventy years, primarilyfor use with vinyl and other polymeric substances. Significant volumesare sold, and plasticizers are used more than any other type of polymeradditives, particularly in polyvinyl chloride (PVC) applications. PVCcan be formulated into a tremendous number of products and is useful ininnumerable applications. Plasticizers provide versatility to PVC andare key ingredients and tools for the vinyl formulator. They are used toadjust hardness (or softness), impart stain resistance, alter tensileproperties (such as strength, elongation or flexibility) andprocessability as required for a multitude of applications, includingwithout limitation flexible vinyl applications. While hundreds ofplasticizers have been produced, only a few remain having acceptableperformance properties when combined with vinyl or other polymericmaterials.

There are a number of different types of plasticizers: 1) generalpurpose, 2) specialty types (such as high solvators), and 3) secondarytypes (oils) and diluent types (isodecyl benzoate, for example).Plasticizer additives are available in a wide variety of alternativechemistries.

In addition to chemistry type, plasticizers are categorized anddistinguished based on their ability to solvate dispersed solid polymersand/or their gelation and fusion temperatures in plastisols. Gelationand fusion temperatures dictate the speed of production and areinfluenced by the solvating power of the plasticizer. By way of example,the gelation and fusion temperatures of a plastisol containing adibenzoate plasticizer will be lower than a plastisol containing ageneral purpose phthalate, thus enabling speed of processing in thatparticular application.

Plasticizers serve as a vehicle for the dispersion of resin (polymer)particles, such as PVC. The dispersion is initially a two-phase,heterogeneous system. Use of plasticizers in polymeric dispersionspromotes the formation of homogeneous systems and polymer fusion occursupon heating. The higher the solvating power, the lower the temperatureat which a homogeneous system is fused, which, in turn, decreases theresidence time and increases the speed at which polymeric compositionscan be processed into an end product, resulting in a faster, moreefficient and economical process.

General Purpose Plasticizers.

General purpose plasticizers provide an excellent compromise betweenperformance characteristics and economy for most applications. Someexamples include: bis (2-ethylhexyl phthalate) (DEHP or DOP), diisononylphthalate (DINP), dioctyl phthalate (DNOP), diisodecyl phthalate (DIDP),dipropylheptyl phthalate (DPHP), di-2-ethylhexyl terephthalate (DOTP orDEHT), and diisononyl-1,2 cyclohexane dicarboxylate (DIDC or DINCH®) (asdescribed in U.S. Pat. No. 7,855,340). General purpose phthalatesdominate the volume of plasticizers purchased every year and are mostoften selected for compounding flexible vinyl.

Yearly, plasticizer production is in the area of 12 billion pounds, andthe general purpose phthalate DOP accounts for about half of the poundsof plasticizer consumed, despite pressure from health and environmentalissues encountered with the use of general purpose phthalates.

In view of the ongoing scrutiny of phthalate use, a need has developedfor phthalate alternatives. Both DOTP and DIDC are contenders forphthalate replacement in the general purpose market. These twoplasticizers are considered “next generation”, general purpose“non-phthalate” plasticizers. Even though DOTP, chemically, is aphthalate, it is not an orthophthalate, the use of which is subject toincreasing regulatory pressure. These “next generation” phthalatealternatives are viable; however, they do not always give theperformance desired in vinyl compositions, particularly in plastisols(i.e., they have poorer compatibility, slow speed, high geltemperatures, low gel strength). Blends of plasticizers can be used toadjust performance, although there may be some limits to this approach.

In addition to DOTP and DIDC, sustainable, “green” types of plasticizersare also contending for the general purpose plasticizer market. Examplesinclude plasticizers based on castor oil and soybean oil.

Some applications, however, require performance that cannot be achievedby use of a general purpose plasticizer alone. Applications that requirebetter resistance to oils and solvents are one such example. Generalpurpose phthalates are easily extracted by nonpolar solvents such ashexanes, such that alternative plasticizers would be a much betterchoice. There is also a need for plasticizers that are higher solvatorsfor PVC and other polymer applications.

Specialty-type Plasticizers.

Specialty type plasticizers have been developed to fulfill the need forhigh solvators, the most popular being lower molecular weightphthalates. An example of such a plasticizer is butyl benzyl phthalate(BBP), which is often employed as a high solvating plasticizer.Di-n-butyl phthalate (DBP) and diisobutyl phthalate (DIBP) are alsouseful high solvator, specialty type plasticizers. Other examples ofnon-phthalate, high solvating plasticizers include some citric acidesters, alkyl sulfonic acid esters, and certain phosphates. Dibutylterephthalate (DBTP) and N-alkyl pyrrolidones have also been proposed asa specialty type, high solvator plasticizers.

All of the high solvator plasticizers (regardless of type) add value tovinyl compositions that traditional general purpose plasticizers cannot.Even so, many of the high solvator plasticizers are phthalates, forwhich safer alternatives are being sought.

Benzoate Ester Plasticizers.

Benzoate ester plasticizers have also been developed as specialty typeplasticizers. Benzoate plasticizers have been recognized since the1940's as useful plasticizers for PVC applications, and subsequentlysome of these benzoate plasticizers were commercialized. Benzoateplasticizers are well established and have now been in use in PVCapplications for decades. By their nature, benzoate plasticizers arenon-phthalates; however, they were not created nor specificallyestablished on that basis and were in use well before the demand forphthalate alternatives began. Benzoate plasticizers includemonobenzoates and dibenzoates, among others.

Monobenzoate esters useful as plasticizers include: isodecyl benzoate,isononyl benzoate, and 2-ethylhexyl benzoate. “Half ester” monobenzoatesinclude dipropylene glycol monobenzoate and diethylene glycolmonobenzoate, which are byproducts of the production of dibenzoates, butwhich, most of the time, are not objects of production. Monobenzoatesare not generally noted for being high solvators, although they may beused in conjunction therewith. Monobenzoates are also not as useful asdibenzoate plasticizers, because they are less compatible than thecorresponding dibenzoate with PVC. However, the half esters arecompatible with emulsions polymers, such as acrylic and/or vinyl esterpolymers.

Classically, dibenzoate plasticizers function well as high solvatingplasticizers and are recognized today as some of the best high solvatorsfor PVC applications. Historically, diethylene glycol dibenzoates(DEGDB) and dipropylene glycol dibenzoates (DPGDB) esters are well knownand have been used in many applications in the past, including the vinylindustry. DEGDB is an excellent plasticizer, but due to its high freezepoint, blends with DPGDB were also developed to capitalize on theutility and lower cost of DEGDB. Several years ago a blend of DEGDB,DPGDB and triethylene glycol dibenzoates (TEGDB) was introduced as ahigh solvating dibenzoate blend.

State of the Art.

Benzoate ester plasticizers, alone or in a blend with otherplasticizers, are commercially available and are described in theliterature and in prior patents. Plastisol and organosol compositions,adhesives, caulks, polishes, inks, and a wide variety of coatingscontaining benzoate plasticizers are also known in the art.

By way of example, U.S. Pat. No. 4,950,702 to Arendt discloses plastisolcompositions comprising a polyvinyl resin plasticized with dipropyleneglycol monomethyl ether benzoate or tripropylene glycol monomethyl etherbenzoate.

U.S. Pat. No. 5,236,987 to Arendt discloses the use of isodecyl benzoateas a coalescent agent for use in paint compositions and in thepreparation of plastisols.

U.S. Pat. No. 5,319,028 to Nakamura et al. describes a plastisolcomposition that comprises PVC resin and a plasticizer used singly, orin combination, that may include, among other plasticizers, glycolderivatives, such as DEGDB, DPGDB, and TEG di-(2-ethylhexoate).

The use of dibenzoate esters alone or in combination with theircorresponding monobenzoate ester is described in U.S. Pat. No. 5,676,742to Arendt et al., which discloses plasticized aqueous polymercompositions useful as latex caulks.

Dibenzoate plasticizer blends used as the primary plasticizer for aplastisol composition are described in U.S. Pat. No. 5,990,214 to Arendtet al., which discloses blends comprising the dibenzoates of both DEGand triethylene glycol for use in plastisol applications.

U.S. Pat. No. 7,812,080 to Arendt et al. describes a plastisol having adispersed phase and a liquid phase, the liquid phase includingdibenzoate plasticizer blends having a hydroxyl number of about 30 orgreater indicating a higher half ester monobenzoate content. Theplastisols provided are stated to be effective for providing a foamedcomposition having an improved color.

U.S. Pat. No. 6,583,207 to Stanhope et al. describes the addition of atleast about 30 wt. % of DEG or DPG half ester monobenzoates to DEGdibenzoate to form a liquid mixture at around 28° C. Similarly, U.S.Pat. No. 7,056,966 to Stanhope et al. describes the addition of at least20 wt. % of at least one half ester monobenzoate to at least onedibenzoate to form a liquid mixture at around 28° C. These liquidmixtures are described as effective plasticizers for aqueous polymercompositions, such as adhesives and caulk.

U.S. Pat. No. 7,071,252 to Stanhope et al. describes the use of halfester monobenzoates as secondary plasticizers for non-aqueous andsolvent-less plastisols containing primary plasticizers.

U.S. Pat. No. 7,872,063 to Strepka et al. describes a film-formingcomposition, such as a polish, coating, adhesive or ink, comprising atleast one acrylic or vinyl acetate polymer as the film-forming componentin combination with a plasticizer blend comprising an aromaticdibenzoate, DEGDB and DEGMB.

U.S. Pat. No. 7,629,413 to Godwin et al. describes a PVC plastisolcomposition comprising C9-C11 alkyl benzoates in combination withphthalate plasticizers to reduce viscosity and reduce staining problemsassociated with the phthalates.

U.S. Pat. No. 8,034,860 to Arendt et al. describes an organosolplastisol composition comprising plasticizers that are diesters ofbenzoic acid and dihydric alcohols in combination with an organicdiluent. Monoesters of benzoic acid and monohydric alcohols are alsodescribed as auxiliary plasticizers.

U.S. Pat. Publication No. 2009/0036581 to Joshi et al. describesplasticizers for polymers based on blends of the mono- and di-benzoatesof 2,2,4-trimethyl-1,3-pentanediol, containing a minimum of 87 weightpercent of the dibenzoate, which can be used in combination withdipropylene glycol benzoates.

In sum, benzoate esters, including DPGDB and DEGDB blends, have beenused in many applications. Dibenzoate plasticizers provide improvedprocessability, fast fusion and stain resistance, among other propertiesthat are favorable for many polymer applications.

The focus of the present invention is on non-phthalate, high solvatorplasticizer compositions, since general purpose phthalateplasticizers—although widely used, effective and economical in vinyl—arenot efficient solvators. Moreover, the use of phthalates has been underincreased attack by governmental agencies due to environmental, healthand safety issues associated with their use. And, while the specialtyphthalate plasticizer butylbenzyl phthalate (BBP) was widely regarded asthe holy grail of plasticizers in that it was an excellent (high)solvator with low viscosity and a desirable rheology profile, it, too,has now come into disfavor as a potential teratogen and toxin.

Accordingly, there continues to be a need for alternatives to currentlyavailable high solvating phthalate plasticizers and, hence, benzoateplasticizers and blends thereof are viable alternatives due to theirhigh solvating properties.

Of particular interest in the present invention are dibenzoateplasticizers, which, as discussed above, have been known and used fortheir high solvating properties in a variety of applications. Even so,dibenzoate use in plastisols may be limited by high plastisol viscosityand undesirable rheology over time as the plasticizer continues tosolvate. As the plastisol composition ages, it is rendered more and moreviscous. In addition, high solvator plasticizers may be less heat and UVlight stable. They are also denser than general purpose plasticizers andhave a higher migration than general purpose types when used inpolymeric products, such as plastisols.

These limitations are described in the '860 to Arendt et al. mentionedabove. The '860 patent describes a plastisol comprising a dispersedpolymer and a DEG/DPG dibenzoate blend that resulted in a 25-foldincrease in plastisol viscosity, which was far too viscous forprocessing using conventional equipment. The publication furtherdiscloses a plastisol composition comprising a dispersed polymer,dibenzoate plasticizers (among others) and an organic diluent (solvent),wherein viscosity increase was avoided or reduced by selecting andmatching components based upon specific differences between a) theHildebrand solubility parameter of the polymer and b) the weightedaverage of the Hildebrand solubility parameters of the organic diluent(solvent), plasticizers and any other liquid ingredients present in theplastisol. The difference between a and b is required to be withinspecified limits to avoid too high a plastisol viscosity on the onehand, or the possibility of exudation of liquids from articles formedfrom the plastisol on the other hand. The plasticizer was selected fromthe group consisting of diesters of benzoic acid and dihydric alcohols,such as propylene glycol, and oligomeric ether glycols, such asdiethylene glycol, triethylene glycol, dipropylene glycol and1,3-butanediol, as well as diesters of phthalic acid and monohydricalcohols.

In response to continued needs in the PVC industry, a new dibenzoatetriblend platform has been developed which can been optimized forperformance and handling in polymeric compositions, and which providesan improvement over some traditional benzoate plasticizers and blends,in particular with respect to plastisol rheology. The novel blendcomprises three dibenzoate plasticizers that have surprisingly fewerviscosity limitations than would be expected based on the viscosities ofthe individual components. A blend of dibenzoate plasticizers, i.e.,DEGDB and DPGDB in specified ratios, forms the base of the inventiveplasticizer triblend in combination with 1,2-propylene glycoldibenzoates (PGDB). 1,2-Propylene glycol dibenzoate is a known componentpreviously used alone with PVC or in plasticizer blends unrelated to thepresent inventive triblend. 1,2-Propylene glycol dibenzoate was alsoknown as a flavoring agent for beverages as described in U.S. Pat. No.3,652,291 to Bedoukian.

The inventive triblend is useful as a high solvating plasticizer inplastisol applications and, unexpectedly, the combination provides lowerviscosity and improved rheology characteristics in plastisols over whatwould be expected based on the rheological characteristics of each ofthe individual components of the triblend. The novel triblend iscompatible and efficient when used in plastisol formulations andprovides improved processability, whether used as a primary plasticizeror as a blending plasticizer in conjunction with poor solvatingplasticizers. The novel triblend of DPGDB, DEGDB, and PGDB has not beenutilized in the past.

The focus of the present invention is on the use of the inventive blendto formulate novel plastisol compositions for use in flooringapplications. However, the invention is not limited to flooringapplications. The inventive plasticizer triblend can be usedindividually and in blends with other plasticizers in applications thatinclude but are not limited to: adhesives, caulks, architecturalcoatings, industrial coatings, OEM coatings, other types of plastisols,sealants, overprint varnishes, polishes, inks, melt compounded vinyl,polysulfides, polyurethanes, epoxies, styrenated acrylics andcombinations thereof. Other applications will be evident to one skilledin the art based upon the disclosure herein.

Principle applications for the inventive triblend include:

PVC: the inventive triblend has been shown to be a high solvatingplasticizer, with unexpectedly lower viscosity than what would beexpected based upon the viscosities of the individual components.

Coatings: the inventive triblend has been shown to have utility incoating technology, primarily as a low VOC coalescent, that hasexcellent compatibility with the polymers utilized in the architecturaland industrial coatings industry. This application is the subject of aco-pending application. The inventive triblend may also be used in othercoatings and film-forming compositions, such as polishes, inks andoverprint varnishes, among others.

Adhesives: the inventive triblend is highly compatible and has goodviscosity response and Tg (glass transition temperature) suppression.

Sealants and Caulks.

It is an object of the invention to provide a non-phthalate plasticizercomposition for use as a primary plasticizer or as a specialtyplasticizer in polymeric compositions traditionally requiringplasticizers, including without limitation PVC applications.

It is another object of the invention to provide a non-phthalateplasticizer composition that is compatible with a wide range ofpolymeric compositions, has high solvating properties, and is useful asa specialty blending plasticizer to improve the compatibility andprocessability of poor solvating plasticizers.

It is yet another object of the invention to provide a non-phthalateplasticizer composition for use in plastisols, having high solvatingproperties, while minimizing the attendant disadvantages of highviscosity and poor rheology associated with the use of high solvators inplastisols.

It is a further object of the invention to provide a plastisolformulation utilizing a non-phthalate plasticizer, which allows fasterprocessing and economic efficiencies to be achieved.

It is yet another object of the invention to provide a plastisolformulation utilizing a non-phthalate plasticizer, which provides highertensile strength and stain and extraction resistance.

Still further objects of the invention are to provide an adhesiveformulation and an overprint varnish utilizing the non-phthalateplasticizer triblend of the invention.

Other objects of the invention will be apparent from the descriptionherein.

SUMMARY OF THE INVENTION

Plasticizer blends of the present invention comprise unique blends ofthree dibenzoate esters: diethylene glycol dibenzoate (DEGDB),dipropylene glycol dibenzoate (DPGDB), and 1,2-propylene glycoldibenzoate (PGDB). These plasticizers are compatible with each other andwith various polymers such as elastomers, thermoplastics, andthermosets; such as, for example, polyvinyl chloride and copolymersthereof; various polyurethanes and copolymers thereof; variouspolysulfides; various polyacrylates and copolymers thereof; variouspolysulfides and copolymers thereof; various epoxies and copolymersthereof; and vinyl acetate and copolymers thereof.

The inventive plasticizer triblend functions in PVC applications as ahigh solvator, but with unexpectedly lower viscosity and improvedrheology characteristics than would be expected based upon theindividual triblend components alone.

In one embodiment, the invention is directed to a novel plastisolcomposition, comprising a polymer dispersed in a liquid phase consistingof the inventive triblend, wherein the viscosity of the plastisol islower than that which would have been expected with the use of PGDBblended with a 4:1 DEGDB/DPGDB blend.

In another embodiment, the invention is directed to an adhesivecomposition comprising a polymer dispersed in a liquid phase consistingof the inventive triblend, wherein the Tg of the adhesive isunexpectedly lower than that achieved with PGDB alone and similar tothat achieved with the 4:1 DEGDB/DPGDB blend. The inventive plasticizertriblend is more efficient than PGDB alone in softening the adhesivepolymer resulting in efficiencies in manufacturing and reduced costs.

In yet another embodiment, the invention is directed to a traditionalcoating composition comprising a polymer dispersed in a liquid phaseconsisting of the inventive triblend, wherein the VOC content of thecoating is substantially reduced as compared to other conventionalcoalescents and plasticizers.

In still a further embodiment, the invention is directed to a screen inkor an overprint varnish composition comprising a polymer dispersed in aliquid phase consisting of the inventive triblend.

The improved properties attributable to the use of the plasticizertriblend described herein include efficient Tg suppression (foradhesives), faster processing time than that achieved with generalpurpose types of plasticizers, reduced plasticizer freeze point, lowgelation and fusion temperatures, low VOC content, unexpectedly lowerapplication viscosity, higher tensile strength than that achieved withgeneral purpose phthalates, and excellent stain and extractionresistance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a chart reflecting Brookfield Viscosity, 20 RPM, 23° C. forthe inventive triblend as compared to DINP, DIDC or DINCH®, BBP, adibenzoate diblend (DEGDB/DPGDB), and PGDB.

FIG. 1A is a chart reflecting the 7 day/initial viscosity ratios for theinventive triblend as compared to DINP, DIDC, BBP, a dibenzoate diblend,and PGDB.

FIG. 2 is a 1-day shear rate scan (70 PHR) reflecting results obtainedfor the inventive triblend, DINP, DIDC, BBP, a dibenzoate diblend(DEGDB/DPGDB), and PGDB.

FIG. 3 is a graph reflecting gel/fusion curves for the inventivetriblend, DINP, DIDC, BBP, a dibenzoate diblend (DEGDB/DPGDB), and PGDB.

FIG. 4 is a chart reflecting Shore A Hardness Data for the inventivetriblend, a dibenzoate diblend (DEGDB/DPGDB), DINP, DIDC, and BBP.

FIG. 5a is a chart reflecting tensile strength (psi) data for theinventive triblend, a dibenzoate diblend (DEGDB/DPGDB), PGDB, DINP, DIDCand BBP.

FIG. 5b is a chart reflecting elongation (%) data for the inventivetriblend, a dibenzoate diblend (DEGDB/DPGDB), PGDB, DINP, DIDC and BBP.

FIG. 5c is a chart reflecting 100% modulus data for the inventivetriblend, a dibenzoate diblend (DEGDB/DPGDB), PGDB, DINP, DIDC and BBP.

FIG. 6 is a graph reflecting volatility data for the inventive triblend,a dibenzoate diblend (DEGDB/DPGDB), DINP, DIDC and BBP.

FIG. 7 is a chart reflecting extraction resistance data for theinventive triblend, a dibenzoate diblend (DEGDB/DPGDB), DINP, DIDC andBBP in heptane, peanut oil and 1% IVORY soap.

FIG. 8 is graph reflecting Brookfield Viscosities (mPa's) for a typicalbasic spread coating type formulation comprising the inventive triblend,a dibenzoate diblend (DEGDB/DPGDB), PGDB, DINP or BBP.

FIG. 9 is an initial shear rate scan reflecting viscosities (mPa's) overvarious shear rates (1/s) for a typical basic spread coating typeformulation comprising the inventive triblend, a dibenzoate diblend(DEGDB/DPGDB), PGDB, DINP or BBP.

FIG. 10 is a graph reflecting gel/fusion curves for a typical basicspread coating type formulation comprising the inventive triblend, adibenzoate diblend (DEGDB/DPGDB), PGDB, DINP or BBP.

FIG. 11 is a chart reflecting stain resistance (ΔE) studies comparingthe stain resistance of DINP, BBP, a dibenzoate diblend (DEGDB/DPGDB),PGDB, and the inventive triblend in the resilient flooring plastisolformulation using asphalt, KIWI® Brown Shoe polish, mustard and 1% OilBrown stainants.

FIG. 12 is a graph reflecting the results of a basic rheology screen fora basic plastisol formulation comprising the inventive triblend, adibenzoate diblend (DEGDB/DPGDB), PGDB, DINP, DIDC, BBP, DBT, or DOTP.

FIG. 13 is a graph reflecting gel fusion curves for a basic plastisolformulation comprising the inventive triblend, a dibenzoate diblend(DEGDB/DPGDB), PGDB, DINP, DIDC, BBP, DBT, DOTP or an alkyl pyrrolidone(300).

FIG. 14 is a graph reflecting a basic rheology screen for the inventivetriblend at 1 hour and 1 day in a basic spread coating formulation.

FIG. 15 is a graph reflecting a gel/fusion curve for the inventivetriblend in a basic spread coating formulation.

FIG. 16 is a photograph reflecting stain resistance of vinyl with PGDB,a dibenzoate diblend (DEGDB/DPGDB), the inventive triblend, DINP, aDINP/DIHP blend, and BBP.

FIG. 17 is a graph reflecting gel/fusion curves for a plastisol screenink comprising the inventive triblend, DINP, and a 50:50 blend of theinventive triblend with DINP.

FIG. 18 is a graph reflecting rheology data obtained for a plastisolscreen ink comprising the inventive triblend, DINP, and a 50:50 blend ofthe inventive triblend with DINP.

FIG. 19 is a graph showing Tg suppression curves for a PVAc homopolymercomprising the inventive triblend, a commercial dibenzoate diblend(KFLEX® 850S) or PGDB.

FIG. 20 is a graph showing Tg suppression curves for a PVA/E copolymercomprising the inventive triblend, a commercial dibenzoate diblend(KFLEX® 850S) or PGDB.

FIG. 21 is a chart reflecting viscosity levels obtained for a PVAchomopolymer at 1 day, using 10% or 15% plasticizer levels, comprisingthe inventive triblend, a commercial dibenzoate diblend (KFLEX® 850S),or PGDB.

FIG. 22 is chart reflecting viscosity levels obtained for a PVA/Ecopolymer at 1 day, using 5% or 10% plasticizer levels, comprising theinventive triblend, a commercial dibenzoate diblend (KFLEX® 850S), orPGDB.

FIG. 23 is a chart reflecting Konig Hardness Data on aluminum panel foran overprint varnish formulation comprising the inventive triblend (6%loading), a dibenzoate diblend (DEGDB/DPGDB) (6% loading), DEGDB,diethylene glycol monomethyl ether, 2-EHB, a monobenzoate, dipropyleneglycol monomethyl ether, diethylene glycol monobutyl ether or nocoalescent.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a new blend of three plasticizers:DEGDB, DPGDB and 1,2-propylene glycol dibenzoate (PGDB), in the amountsand/or ratios discussed herein. The plasticizers of the presentinvention can generally be utilized with numerous thermoplastic,thermoset, or elastomeric polymers often as an alternative forconventional plasticizers. In particular, the inventive triblend may beused to prepare a reduced viscosity PVC or acrylic plastisol inaccordance with the present invention.

In addition to PVC and acrylic plastisols, the inventive triblend may beuseful in other polymeric compositions, including but not limited tovarious vinyl polymers such as polyvinyl chloride and copolymersthereof, vinyl acetate, vinylidene chloride, diethyl fumarate, diethylmaleate, or polyvinyl butyral; various polyurethanes and copolymersthereof; various polysulfides; cellulose nitrate; polyvinyl acetate andcopolymers thereof; and various polyacrylates and copolymers thereof.

Acrylic polymer compositions for various applications may also be usedwith the inventive triblend and include various polyalkyl methacrylates,such as methyl methacrylate, ethyl methacrylate, butyl methacrylate,cyclohexyl methacrylate, or allyl methacrylate; or various aromaticmethacrylates, such as benzyl methacrylate; or various alkyl acrylates,such as methyl acrylate, ethyl acrylate, butyl acrylate, or 2-ethylhexylacrylate; or various acrylic acids, such as methacrylic acid andstyrenated acrylics.

Other polymers for which the inventive triblend may be useful as aplasticizer include epoxies, phenol-formaldehyde types; melamines; andthe like. Still other polymers will be evident to one skilled in theart.

For purposes of the invention, “plastisol” means a liquid polymercomposition comprising a particulate form of at least onenon-crosslinked organic polymer dispersed in a liquid phase comprising aplasticizer for the polymer. The present invention is not restricted toany particular polymer, although the invention may be described in termsof vinyl polymers.

As used herein, “organosol” means a plastisol comprising, in addition tothe plasticizer, a liquid hydrocarbon, ketones, or other organic liquidsto achieve desired processing viscosity in amounts greater than about 5wt. %.

As used herein, “high solvator” or “high solvating” is a term thatdescribes the plasticizer's efficiency in penetrating and softening apolymer, “higher” solvators softening the polymer faster, thusfacilitating the formation of a homogenous phase.

The preferred dibenzoates of the invention are DEGDB, DPGDB, and1,2-propylene glycol dibenzoate (PGDB). PGDB was previously known foruse as a high solvating plasticizer for vinyl compositions alone or incombination with other plasticizing materials not related to theinvention disclosed herein. Use of PGDB (defined as 1,2-propylene glycoldibenzoate) in the inventive dibenzoate triblend is key, since use ofother propylene glycol dibenzoates do not provide the lower freeze pointdiscussed below.

One feature of the inventive plasticizer triblend is a lower freezepoint than some currently available commercial dibenzoate blendscontaining DEGDB. Almost all newer commercial dibenzoate blends containDEGDB as a base for the blend due to excellent solvating characteristicsand the drive for cost savings. However, pure DEGDB freezes above normalroom temperature (28° C.), thus hampering its use. The freeze point ofthe inventive triblend (initial onset of freezing) as compared tocurrently available typical dibenzoate blends are as follows:

Inventive triblend: +6° C.

typical dibenzoate diblend: +12° C.

Handling dibenzoate blends containing DEGDB can be an issued compared totypical plasticizers such as phthalate esters. As such, the lower freezepoint achieved by the inventive triblend provides a distinct advantageover currently available dibenzoate blends.

While not wishing to be bound by any particular theory, it is believedthat the addition of PGDB to the DEGDB/DPGDB blend lowers the freezingpoint considerably (from −12° C. to −6° C.), which provides considerableadvantages in cold weather handling for which some dibenzoates andblends were not previously considered.

The amounts of the individual plasticizers in the inventive blends canvary broadly depending on end use and properties desired. Thus, for thetriblend, the amount of DEGDB can vary from about 10% to about 90% byweight based upon the total weight of the triblend composition, butpreferably is present in amounts greater than about 60% by weight.Higher amounts of DEGDB than either of the other two plasticizers arepreferred due to cost considerations, DEGDB being far less expensivethan PGDB and DPGDB. The amount of DPGDB can generally vary from about1% to about 50% by weight based upon the total weight of the triblend,but preferably is present in amounts greater than about 15%. The amountof PGDB can vary broadly such as from about 10% to about 90% by weightbased upon the total weight of the dibenzoate triblend, but preferablyis present at about 20 wt. %. PGDB is also lower in cost than DPGDB.

One preferred embodiment is shown below:

a. 1,2-PGDB 20 wt. %

b. DEGDB/DPGDB 80/20 80 wt. %

The triblend can be prepared in any conventional manner known to oneskilled in the art, including by simply blending the three componentstogether, or by forming them together in situ.

DPGDB is commercially available as K-FLEX® DP made by Emerald KalamaChemical, UNIPLEX® 988 made by Unitex Chemical Corp., SANTICIZER® 9100made by Ferro, and FINSOLV® PG-22 made by Finetex, Inc. DEGDB iscommercially available as K-FLEX® DE, and UNIPLEX® 245. PGDB iscommercially available as UNIPLEX® 284, and has been manufactured in thepast as K-FLEX® MP.

The inventive triblend can be utilized with numerous different types ofpolymers and in different applications that require plasticizers. Thetotal amount of the dibenzoate triblend, for example, would rangebroadly depending on the application, generally from about 1 to about300, desirably from about 10 to about 100, and preferably from about 20to about 80 parts by weight for every 100 total parts by weight of theone or more thermoplastic, thermoset, or elastomeric polymers, includingwithout limitation those identified above. A particularly preferredembodiment for a plastisol includes 70 parts by weight of plasticizerfor every 100 total parts by weight of polymer(s) or roughly 40 wt. %.

The inventive triblend compositions can be utilized in coatings,depending on the nature of the coating, in amounts up to about 20% ofthe polymer solids in the system.

The inventive triblend can be utilized in aqueous adhesives in amountsup to about 50 wt. %, based upon the total weight of the adhesive.

The inventive triblend can be utilized in overprint varnishes in amountsup to about 20 wt. %, based upon the total weight of the overprintvarnish.

The inventive triblend may be, but is not required to be, blended withvarious other conventional plasticizers to enhance or augment propertiesof polymeric compositions, including but not limited to improvingcompatibility and processability in a plastisol. Conventionalplasticizers include, but are not limited to, various phthalate esters,various phosphate esters, various adipate, azelate, oleate, succinateand sebacate compounds, terephthalate esters such as DOTP,1,2-cyclohexane dicarboxylate esters, various epoxy plasticizers,various fatty acid esters, various glycol derivatives, varioussulfonamides, and various hydrocarbons and hydrocarbon derivatives thatare often utilized as secondary plasticizers. Monobenzoates, such asisononyl benzoate, isodecyl benzoate, 2-ethylhexyl benzoate, and2,2,4-trimethyl-1,3-pentanediol diisobutyrate can also be blended withthe inventive triblend. In particular, the inventive triblend is usefulas a blending plasticizer for addition to poorer solvating plasticizers,such as DIDC and DOTP among others, to improve compatibility andprocessability in plastisol applications.

The inventive triblend may also contain various amounts of conventionaladditives such as antioxidants, heat stabilizers, flame retardants,surfactants and the like. Additives amounts can generally vary widelyand often range from about 0.1 to about 75 parts by weight for every 100parts by weight of the blend.

The dibenzoate blends of the present invention can be utilized whereverconventional plasticizers are currently used. Desirably, they areutilized in adhesives, caulks, architectural and industrial coatings,plastisols, overprint varnishes, inks, melt compounded vinyl,polysulfides, polyurethanes, epoxies, or any combinations thereof. Otheruses will be evident to those skilled in the art.

The invention is further described in the examples below.

EXAMPLES Experimental Methodology

Plastisol and Vinyl Preparation

The plastisols made for the basic screen were prepared in a Hobart ModelN-50 mixer. A ten minute mix at speed one (1) was used. A high speeddisperser was also used to prepare other plastisols evaluated employinga ten minute mix at 1000 RPM's. All of the plastisols were degassed at 1mmHg until as completely air free as possible.

The vinyl for the basic screen was fused in a closed mold at a thicknessof 1.2 mm at 177° C. for 15 minutes in a Blue M oven. Vinyl for thestain testing was fused in a Mathis oven at a thickness of 0.5 mm at204° C. for 2.5 minutes. The air flow was set at 1500 RPM's.

Tests/Evaluations

Unless otherwise indicated in specific examples, the general testsand/or methodologies described below were used in evaluating theperformance of the inventive plasticizers in comparison to currentlyavailable plasticizers. The tests and methods are known to one skilledin the art.

Ability to Degas—After mixing the plastisol, degree and ease ofdegassing was determined. About ten milliliters were placed in a vacuumcylinder and a 1 mmHg vacuum was applied. Height of the rise in mL wasdivided by the starting volume and that value was reported. The time tofoam break was noted.

Viscosity and Rheology: Low shear—Brookfield RVT, 20 RPM's, 10revolution reading. ASTM D1823. High shear—TA AR2000ex used. Parallelplates were set at appropriate gap (350 microns). Shear to 1000 sec⁻¹.

Gel/Fusion: TA AR2000ex in oscillatory mode. Parallel plates were set atappropriate gap (600 microns). The test temperature was started at 40°C. and heated at a rate of 5° C./minute to 220° C.

Gel temperature—Hot bench type test wherein a thin bead of a plastisolwas applied to a temperature gradient plate and after three minutes cutswere made across the bead. The temperature at which the cut in theplastisol did not re-fuse was the gel temperature, i.e., the plastisolwas “gelled.”

Compatibility: Loop—ASTM D3291. Roll—a tight loop of vinyl was rolledwith absorbent paper, then placed in an oven at 60° C. for three days.Compatibility was judged on degree of exudation in sum.

Efficiency—Shore A—ASTM D2240; Tensile—ASTM D638, type IV die, 50.8cm/minute pull rate.

Permanence—Extraction resistance, ASTM 01239. Extractants—Peanut oil (24hour exposure at RT); 1% IVORY soap solution (24 hours at 50° C. and 4hours dry at 50° C.); heptane at RT (24 hours, 4 hours dry at 50° C.).Activated charcoal volatility, ASTM 01203 was evaluated at 1, 3, 7, 14,21, and 28 days.

Heat stability testing was conducted in a Mathis oven at 195° C. with ablower speed of 1500 RPM's at the test intervals indicated. The time tofirst yellowing and to brown were noted.

Stain testing: A 1% solution of oil brown dye dissolved in mineralspirits was used as the staining agent. The staining agent was appliedto the vinyl and held in place with a tissue for 30 minutes. The stainwas wiped from the vinyl, the vinyl was wiped clean with mineralspirits, and pictures were taken to record results.

Examples 1-6

For examples 1-6, the inventive triblend dibenzoate plasticizer (X20),comprising 20 wt. % 1,2-propylene glycol dibenzoate and 80 wt. % of an80/20 DEG/DPG dibenzoate blend, was evaluated to determine basicperformance parameters versus standard controls, to facilitateformulation directions. Controls used in examples 1-6 evaluationsincluded butylbenzyl phthalate (BBP), diisononyl phthalate (DINP), anddiisononyl-1,2-cyclohexane dicarboxylate (DIDC). Also separatelyevaluated, in addition to the inventive triblend, were a DEGDB/DPGDBdiblend plasticizer (X250; 4:1 DEG dibenzoate:DPG dibenzoate ratio) andPGDB (X100>98%), both of which are components of the inventive triblend.

Tests conducted in examples 1-6 include: compatibility (loop and rollspew); efficiency (Shore A, tensile properties); permanence (extractionand volatility); and processability (viscosity, viscosity stability,shear rate/rheology and gel/fusion).

The basic plastisol formulation evaluated in examples 1-6 is shown inTable 1, below:

TABLE 1 Basic Plastisol Formulation Material PHR Dispersion Resin, K76100 Plasticizer 70 Ca/Zn stabilizer 3

The use of a basic plastisol formulation was to demonstrate interactionsof plasticizers with PVC without interference from other additives,other than a required heat stabilizer.

Example 1—Brookfield Viscosity

Brookfield Viscosity tests showed an expected higher initial viscosityfor the high solvating plasticizer individual components, i.e., theDEGDB/DPGDB diblend (X250) and the PGDB (X100) showed higher viscosityover all controls initially and at day 1. The 7 day/initial ratio wasalso higher for the X250 and X100 individual components over the DINPand DIDC controls, but not for BBP. It was expected that the viscosityof the triblend (X20), i.e., the combination of the DEGDB/DPGDB andPGDB, would be additive, i.e., somewhere between (based on the blendratios) the individual components' viscosities. Unexpectedly, the 7day/initial viscosity ratio was lower for the inventive triblend thanfor BBP, or either the DEGDB/DPGDB (X250) and PGDB (X100) componentalone and comparable to that obtained for DINP and DIDC. The lower theratio, the more stable the plasticizer viscosity. Generally, highsolvators are not expected to have a lower ratio, but the inventivetriblend did.

Example 2—One-Day Shear Rate Scan

Results from the one-day shear rate scan (70 PHR) are shown in FIG. 2.As shear rate was increased, higher and higher viscosity was expected.For the controls, viscosity for DINP and DIDC remained level, while BBPincreased slightly and leveled off. For the DEGDB/DPGDB (X250) and PGDB(X100), viscosity rose sharply and declined sharply for X100, while X250rose slightly less sharply and declined modestly at higher shear rates.Again, unexpectedly, the 1-day shear rate scan for the triblend (X20)was better than that obtained for either component alone, (i.e., theDEGDB/DPGDB (X250) blend and the PGDB (X100)) and had a curve similar toBBP, albeit at a higher viscosity. Overall, PGDB (X100) had much poorerrheology as compared to the inventive triblend as reflected in FIG. 2.

Example 3—Gel/Fusion

Gel fusion data illustrates the relative solvation characteristics ofvarious plasticizers. FIG. 3 and Table 2 show the results of thegel/fusion evaluation, which reflected comparable results for theindividual components (X250 and X100) and the triblend (X20) as comparedto the BBP control that is considered an industry standard. The resultsalso showed that the novel triblend (X20) and PGDB (X100) were muchbetter solvators than the DEGDB/DPGDB (X250) blend.

TABLE 2 Gel Fusion Data Initial Inflection G′ Maximum G′ × G″ Temp TempModulus Temp Plasticizer (° C.) (° C.) (Pa) (° C.) DINP 79 125 3.5 × 10⁵177 DIDC 107 139 2.8 × 10⁵ 181 BBP 61 86 1.1 × 10⁶ 167 X-250 diblendtailored to 59 91 1.0 × 10⁶ 168 PVC industry (not inventive) X-20inventive triblend 58 87 1.2 × 10⁶ 168 X-100 propylene glycol 59 82 1.2× 10⁶ 164 dibenzoate

Fused Vinyl Properties

Example 4—Compatibility Testing

A Loop test, ASTM D3291 was used to determine the compatibility of theplasticizers with PVC. The test temperature was 23° C. and evaluationswere obtained after 1, 3 and 7 days. With the exception of DIDC, none ofthe plasticizers exhibited any exudation. All of the plasticizers wereconsidered compatible using this test.

A Roll test was conducted on the plasticizers. The test temperature was60° C. for 3 days, and evaluations were obtained after 1, 2 and 3 days.All plasticizers except DIDC were compatible by this test. DIDCexhibited heavy exudation.

Example 5—Efficiency Testing

Shore A Hardness data were obtained at 1 second and 10 seconds for allcontrols (BBP, DINP and DIDC), the X250 diblend and the X20 triblend.The results are shown in FIG. 4 and show that the triblend (X20) anddiblend (X250) were as efficient as the controls.

Tensile data obtained for the controls, the diblend (X250), PGDB (X100)and the triblend (X20) are shown in FIGS. 5a (Tensile at Break); 5 b (%elongation); and 5 c (100% modulus). The results show the X20 triblendexhibited superior elongation compared to the dibenzoate blend and mostof the controls, as well as greater tensile strength compared to thecontrols.

Example 6—Permanence Testing

Volatility data obtained for the controls, the diblend (X250) and thetriblend (X20) are shown in FIG. 6. The results show that the X20triblend has moderate volatility compared to the controls.

Extraction Resistance data in heptane, peanut oil and 1% IVORY Soap wasobtained for the controls, the diblend (X250) and the triblend (X20) asshown in FIG. 7. The results show that the X20 triblend had superiorextraction resistance versus the controls in both heptane and peanutoil. Although the extraction resistance of the triblend in IVORY Soapwas poorer than the controls, it was still slightly better when comparedto the diblend.

The results above demonstrated that the inventive triblend, like thedibenzoate diblend, is a high solvator with similar compatibility to thecontrols. In plastisols, both the inventive triblend and the diblenddemonstrated dilatant flow and higher viscosities than general purposeplasticizer controls. Overall, the dibenzoate blends were more volatilethan the general purpose plasticizers, but showed a better extractionresistance to solvents and oils. The dibenzoate blends showed muchbetter fusion characteristics than general purpose plasticizers.

Example 7—Performance in a Spread Coating Type Formulation

Performance characteristics were also evaluated in a typical basicspread coating type formulation. The basic formulation is shown in Table3, below.

TABLE 3 Typical Basic Spread Coating Type Formulation Raw Material PHRDispersion Resin, K76 85 Blending Resin 15 Plasticizer 402,2,4-Trimethyl-1,3-pentanediol diisobutyrate 10 Solvent 3 EpoxidizedSoybean Oil 2 Ca/Zn stabilizer 3

Control plasticizers, DINP and BBP, were compared to the diblend (X250)and PGDB (X100) individual components and to the inventive triblend(X20). Results obtained for Brookfield Viscosity, Initial Shear RateScan, and Gel Fusion are shown in FIGS. 8, 9 and 10. The Gel Fusion datathat was obtained is set forth in Table 4.

TABLE 4 Initial Inflection G′ Maximum G′ × G″ Temp Temp Modulus TempPlasticizer (° C.) (° C.) (Pa) (° C.) DINP 80 118 5.5 × 10⁵ 177 BBP 6388 1.6 × 10⁶ 182 X-250 60 84 1.5 × 10⁶ 168 X-20 61 83 1.5 × 10⁶ 169X-100 62 81 1.6 × 10⁶ 168

Example 8—Stain Resistance

Stain resistance studies were conducted comparing the stain resistanceof DINP, BBP, X250 (diblend), X100 (PGDB) and X20 (triblend) in theformulation of Table 3 to various stainants: asphalt, KIWI® Brown ShoePolish, mustard, and 1% Oil Brown. Oil Brown is an industry standardused to simulate high traffic staining. All of the stainants, except forOil Brown, were placed on the sample and left on for about two hours;the Oil Brown stainant was left on for 30 minutes. Stainants were thenremoved with clean mineral spirits. Color change was evaluated usingdelta E measurements (ΔE or dE), which shows numerically the differencesbetween colors. The inventive triblend showed excellent stain resistancefor asphalt, mustard and 1% Oil Brown. The inventive triblend was betterthan the controls for KIWI® Brown Shoe Polish. Stain resistance resultsare shown in FIG. 11.

Examples 9-11

The following plasticizers were evaluated in examples 9-11:

-   -   Diisononyl phthalate (DINP);    -   Butyl benzyl phthalate (BBP);    -   Di-2-ethylhexyl terephthalate (DOTP);    -   Diisononyl-1,2-cyclohexane dicarboxylate (DIDC);    -   Dibutyl terephthalate (DBTP);    -   N-C8-10 alkyl pyrrolidone (300);    -   X-20 inventive dibenzoate triblend;    -   X-250 dibenzoate diblend tailored to the PVC industry;    -   X-100 1,2 propylene glycol dibenzoate (98%).

In addition to evaluating basic performance data of the aboveplasticizers in a simple plastisol formulation, two other evaluations ofthe plasticizers were conducted—one in a flooring wear layer or typicalspread coating starting formulation and the other in a startingformulation for plastisol screen ink. As above, the basic screen of theplastisol considered the four basic performance parameters:compatibility, efficiency, permanence and processability. The examplesbelow identify basic characteristics used to demonstrate performance.

For the spread coating formula, viscosity, rheology, gel/fusion andstaining were determined; and gel/fusion and rheology were determinedfor the plastisol screen ink formulation.

Table 5 below shows the simple plastisol formulation used to evaluatethe plasticizers. Table 6 below shows the spread coating formula used toevaluate the plasticizers, and Table 7 below shows the plastisol screenink formulation evaluated.

TABLE 5 Simple Plastisol Formulation, Basic Screening Raw Material PHR %Dispersion Resin (Geon ® 121A) 100 58 Plasticizer 70 40 Heat Stabilizer(Mark ® 1221) 3 2

TABLE 6 Spread Coating Starting Formulation Raw Material PHR %Dispersion Resin (Geon 121A) 75 44.9 Blending Resin (Geon 217) 25 15Plasticizer 45 26.9 Isodecyl Benzoate 10 6 Viscosity Control Additive 53 Heat Stabilizer (Mark 1221) 3 1.8 Epoxidized Soybean Oil 4 2.4

TABLE 7 Plastisol Screen Ink, Starting Formulation Raw Material PHR %Dispersion Resin (Geon 121A) 100 30.5 Plasticizer 100 30.5 DiluentPlasticizer (Isodecyl Benzoate) 6 1.8 Dispersant (BYK ® 1148) 2 0.1CaCO₃ 60 18.3 TiO₂ 60 18.3

Example 9—Basic Screening—Plastisol

The results obtained in the basic screening using the simple plastisolformulation (Table 5) are shown below in Tables 8 and 9 and are furtherreflected in FIGS. 12 and 13.

TABLE 8 Performance Properties, Basic Formulation (From Table 5)Property X-20 X-250 X-100 DINP DIDC DOTP DBTP 300 BBP CompatibilityLoop, RT to 28 days C C C C C C PC PC C Roll, 60° C. for 3 days C C C C(SI) I I C C C Efficiency Shore A, 10 second 67 66 66 70 67 70 62 52 65Tensile parameters Tensile at break, MPa 18.8 21.3 18.6 17.9 16.4 12.712.6 11.4 18.8 100% modulus, MPa 6.4 7.2 8.5 7.7 7.3 5.7 3 3.8 6.8Elongation, % 390 350 280 390 340 280 460 410 340 Permanence ExtractionHeptane, 24 hrs, % −2.1 −2.2 −1.4 −37 −41 −41 −8.9 −9.0 −2.9 1% Soap, 24hrs, % −6.2 −6.3 −3.9 −1.6 −1.8 −1.7 −4.5 −11.2 −3.5 Peanut oil. 24hrs., % −1.2 −1.4 −0.6 −5.5 −11.4 −8.7 −4.2 −6.3 −1.4 Act. Char. Vol.,70° C.  1 Day, % −4.0 −4.2 −4.4 −1.6 −1.4 −1.7 −7.0 −3.9 −2.3  3 Day, %−6.4 −6.9 −7.6 −2 −2. −2.1 −14.8 −8.1 −3.9  7 Day, % −9.1 −8.8 −12.5−2.5 −2.8 −2.6 −23.9 −16.3 −6.1 14 Day, % −12.0 −10.7 −18.6 −3.1 −4.−3.4 −29.8 24.7 −10.0 21 Day, % −14.7 −12.3 −22.7 −3.7 −5.1 −4.3 −31.729.3 −13.3 28 Day, % −16.1 −13.7 −24.2 −4.2 −6.1 −4.9 −32.4 31.7 −16.2Processability Viscosity, Brookfield RVT, 20 RPM, 23° C. Initial, 1hour, mPa · s 3740 3720 3120 2070 1060 1630 1390 25150 1980  1 day, mPa· s 4800 5800 4200 2380 1270 1860 2880 Gel 4230 28 day, mPa · s 55005880 7380 2830 2020 2670 7200 Gel 4620 Gel temperature, ° C. 56 58 59 90111 102 57 — 59 Foam/Break, sec. 13/50 9/53 12/>300 6/100 5/135 5/13413/150 7/150 19/86 Heat Stability @ 195° C. Minutes to first color 8 8 810 12 12 8 <6 8 Minutes to brown 14 12 14 16 18 18 16 6 16

TABLE 9 Gel/Fusion Curve Data, Basic Formulation (from Table 5) InitialInflection Gel Peak G′ × G″ Cross Temperature. Temperature, Temperature,Plasticizer ° C. ° C. G′, Pa ° C. X-20 63 91 1.2 × 10⁶ 168 X-250 60 911.0 × 10⁶ 168 X-100 60 81 1.2 × 10⁶ 165 DINP 79 126 3.6 × 10⁵ 179 DIDC107 139 2.2 × 10⁵ 181 DOTP 81 129 2.9 × 10⁵ 177 DBTP 59 87 9.3 × 10⁵ 167300 47 71 3.5 × 10⁵ 158 BBP 61 86 1.1 × 10⁶ 167

The above data shows that the inventive dibenzoate blends were morecompatible than the general purpose non-phthalates with vinyl asillustrated in particular by the loop test and roll test data. Theviscosity/rheology of dibenzoate blends are known to be inferior togeneral purpose plasticizers. However, unexpectedly, the inventivetriblend, a high solvator, exhibited lower than expected viscosity (FIG.12), which provides viable options for formulating plastisols requiringhigh solvator type plasticizers, while minimizing the viscosity/rheologylimitations heretofore known for standard dibenzoate plasticizer blends.

The TA AR2000ex rheometer in oscillatory mode was used to generategel/fusion characteristics to evaluate solvator properties. Table 9lists the data obtained, and FIG. 13 illustrates the curves developedbased upon the data. Based on the data, it is clear that thedibenzoates, BBP, DBTP and 300 were much better solvators than all ofthe general purpose type plasticizers. This demonstrated that gainingfull strength at a lower temperature is possible using the inventiveblends, which translates to speed in production. The classic gel pointdata also demonstrated this point. The 300 was the most aggressive highsolvator, but very low gel strength was developed.

With respect to efficiency, the data obtained shows that dibenzoateblends are somewhat more efficient than DINP, but the other phthalateand high solvators were somewhat more efficient than the dibenzoates. X100 was the least efficient.

With respect to extraction and volatility, the data indicated thatgeneral purpose plasticizers were extracted in massive quantities bysolvent and oils but were good against aqueous solutions. The oppositewas true for high solvators. Also, general purpose plasticizers wereless volatile than the higher solvators. 300 and DBT were very volatilecompared to the other high solvators tested, while BBP was the lowest involatility. The inventive triblend, X 20, and the diblend, X 250, weresimilar in volatility and less volatile, respectively, than BBP. Theactivated charcoal test for volatility is generally run for only oneday. For this example, the test was extended to 28 days to demonstratewhat happens with plasticizers exposed over the long term. Dibenzoateplasticizers always contain residual reaction products that tend to comeoff early with time, which was supported by the data. X 100 was morevolatile than the dibenzoate blends.

The dibenzoate plasticized vinyls and, indeed, all high solvatorplasticized vinyl, exhibited poorer heat stability than the generalpurpose plasticized vinyl's. 300 had extremely poor heat stability.

Overall, in comparison to the other high solvators, the dibenzoatesperformed quite well. This was particularly true in comparison to thenewer non-phthalate type plasticizer, the N-alkyl pyrrolidone (300).

Example 10—Spread Coating Starting Formulation Performance

The plasticizers were evaluated in the spread coating startingformulation reflected in Table 6. FIG. 14 illustrates the excellentrheology and viscosity demonstrated by the inventive triblend, X 20, inthe formulation. FIG. 15 illustrates the excellent gel/fusioncharacteristics obtained for X 20.

FIG. 16 shows the stain resistance of the vinyl with X 100, X 250 and X20 as compared to DINP, a DINP blend with DIHP, and BBP. All of thebenzoates showed excellent stain resistance to Oil Brown dye (indicatorof foot traffic staining). By visual inspection, X 20 plasticized vinylappeared to be the most stain resistant of the dibenzoates.

Example 11—Plastisol Screen Ink Performance

The starting plastisol screen ink evaluated is shown in Table 7. X 20, a50:50 blend of X20 and DINP, and DINP alone were evaluated asplasticizers in the ink formulation. Excellent rheology and viscositywere obtained for X 20 as reflected in FIGS. 17 and 18. Gel/fusionproperties for X 20 were also superior. The blend (X20 and DINP) showedimproved properties as well, illustrating that the high solvator X 20enhanced the performance of the general purpose plasticizer.

Based on all the foregoing, the inventive dibenzoate blends and newgrade glycol dibenzoate offered new options as high solvators for vinylapplications. By nature, the dibenzoates have always been non-phthalatesand are safe products to use with a proven track record of performance.Even so, the new triblend of dibenzoates, X 20, showed good handlingcharacteristics and excellent performance as a high solvator. Plastisolrheology was good and stain resistance of vinyl plasticized with X 20was superior to available general purpose plasticizers and the diblend.

X 250, the diblend, was efficient in vinyl.

X 100, the propylene glycol dibenzoate, offers an excellent highsolvator alternative for vinyl, although it is somewhat less efficientthan the inventive triblend and the diblend. Its high modulus may beadvantageous in some applications.

The inventive triblend has been shown to be an excellent choice as anon-phthalate high solvator plasticizer alternative. It may also be usedin blends with other poor solvating plasticizers to improvecompatibility and processability in a plastisol or as a blendingplasticizer with a variety of other plasticizers to tailor applicationrequirements.

Example 12—Adhesive Evaluation

The performance of the novel triblend, X20, was evaluated in commonlatex adhesives versus established plasticizers. The evaluatedformulations included:

Polymers:

Polyvinyl acetate homopolymer, PVOH protected (PVAc)

Polyvinyl acetate/ethylene copolymer, 0° C. Tg, PVOH protected (PVA/E)

Plasticizers:

X 20, the inventive dibenzoate triblend.

Commercial diblend of DEG/DPG dibenzoates (K-FLEX 850 S).

X100, PGDB

Levels of plasticizer in PVAc evaluated were 5, 10, 15 and 20% on wetadhesive basis. Levels of plasticizer in PVA/E evaluated were 5, 10 and15% on wet adhesive basis. VOC content tests were run on the neatplasticizer. On the adhesive, viscosity response and stability,compatibility (dry film), water reduction, rheology, set and open times,wet tack (rheological determination), T and 180° peel adhesion were run.

PVAc is a standard industry adhesive polymer. Upon addition, theplasticizer became incorporated into the polymer becoming part of theglue. The plasticized glue had a lower glass transition which resultedin a more flexible PVAc polymer, making the glue more efficient. Tgresults obtained at various levels are shown in FIGS. 19 and 20. PGDBwas less efficient in suppressing Tg as compared to the inventivetriblend's Tg suppression. The inventive triblend's Tg suppression wasbetter than expected considering its PGDB content in combination withthe 4:1 DEGDB/DPGDB diblend. The Tg suppression of the inventivetriblend was comparable to that achieved with the commercially availableK-FLEX 850 S, providing a viable option for use in adhesives.

Viscosity results obtained are shown in FIGS. 21 and 22. Excellentviscosity response was shown for the inventive triblend, X20.

Overall, the above-described results showed that the new triblend ofdibenzoates is compatible with typical latex adhesive polymers andperforms similarly and in some cases better than standard binary blends(diblends) of dibenzoates.

Example 13—Overprint Varnish Evaluation

The inventive triblend was evaluated in a waterborne overprint varnish(“OPV”) useful for graphic arts applications. Many of the polymers usedin this industry segment are non-film formers at room temperature;consequently a plasticizer and/or a coalescent is required to help forma film properly to ensure full development of performance propertieswith these hard polymers. Coalescents used in the graphic arts industrytypically have been the more volatile types. Traditionally, glycolethers, phthalate esters (such as BBP) and benzoate esters (2-EHB) havebeen employed as plasticizers/coalescents for OPV's. While thesefunction well, VOC content is an issue. Classically, phthalates such asDBP or BBP have been used in the graphic arts industry but recentlyalternatives are being sought.

Based on its broad range of compatibilities with polymers utilized inthis application, the inventive triblend was evaluated in an OPVformulation, along with other traditional plasticizers or coalescents.

First, the volatility characteristics of neat plasticizers/coalescentswere determined (data not shown). Both the inventive triblend X20 andthe diblend X250 were determined to be less volatile than2,2,4-Trimethyl-1,3-pentanediol monoisobutyrate (TMPDMB) (a historiccoalescent of choice in paint and other coatings), BBP, 2-EHB, andseveral ethers (diethylene glycol monobutyl ether, diethylene glycolmonomethyl ether, ethylene glycol monobutyl ether, and dipropyleneglycol monomethyl ether), making it an acceptable low VOC alternative.

The basic overprint varnish formulation utilized in the viscosityresponse, MFFT and Konig hardness evaluations is shown below in Table10, which reflects the addition of 4% plasticizer/coalescent.

TABLE 10 Basic Overprint Varnish Formulation Ingredient No Coalescent(%) Coalescent (%) Styrene acrylic emulsion, high Tg 64 60 PE waxdispersion, 26% solids 4 4 Resin solution, 34%, high Tg 20 20 Wettingsurfactant 4 4 Defoamer 0.1 0.1 Water 7.9 7.9 Plasticizer/Coalescent 0 4

The viscosity response of the base emulsion is indicative of thecompatibility of the plasticizer/coalescent tested. Viscosity data wasobtained at 1 day aging. The OPV viscosity responses with 4%plasticizer/coalescent were in the range expected for the inventivetriblend X 20 and the diblend X250 and were comparable to DEGDB (in the100-150 mPa range). Viscosity responses for diethylene glycol monobutylether, dipropylene glycol monomethyl ether, and diethylene glycolmonomethyl ether were lower.

The viscosity response to select dibenzoates in the OPV formulation with6% coalescent instead of 4% was also measured. Both the X-250 and X-20OPV's had viscosity of 250 mPa's, which demonstrated that a relativelylow add level (increase of 2%) had a significant impact on OPV viscositywith these types of plasticizers/coalescents.

Table 11 lists the MFFT's (Minimum Film Formation Temperatures) ofvarious OPV formulations with a 4% and a 6% add level. The data showsthat all of the formulations formed films well at room temperatureconditions. Water soluble coalescent types were more effective in MFFTsuppression. As the MFFT depression was somewhat less for thedibenzoates than the ethers, the MFFT's of OPV's with loading at 6% weton X20 and X250 were also determined. The results showed that less thanan additional 2% add would be necessary to achieve MFFT suppressionresults similar to ethers. Most likely, this additional amount would notbe necessary to achieve the desired development of full performancecharacteristics.

TABLE 11 Minimum Film Formation Temperatures Temperature, ° C. OPVCoalescent 4% 6% No Coalescent 31 31 X-20 7.2 −4 X-250 7.2 −5 DEGDB 6.1— 2-EHB 7.2 — Diethylene glycol −1.0 — monomethyl ether Dipropyleneglycol −1.0 — monomethyl ether

One question regarding the use of real plasticizers instead of volatilecoalescents is the effect on parameters such as dry time. Thedry-to-touch time of the OPV's was determined for the inventive triblendX20, the diblend X250, DEGDB, 2-EHB, diethylene glycol monobutyl ether,and dipropylene glycol monomethyl ether. It was noted that there was nosignificant difference in the time to dry-to-touch between the volatileand non-volatile plasticizers or coalescents.

Gloss values were also determined on the OPV's and were found to besimilar for the inventive triblend X20, the diblend X250, DEGDB, 2-EHB,diethylene glycol monobutyl ether, and dipropylene glycol monomethylether.

FIG. 23 displays the Konig hardness data acquired for the OPV'sformulated with plasticizers, including the inventive triblend X20, andtraditional coalescents used in OPV's. Plasticizers are often disfavoredfor use in OPV's based upon the belief that they are more permanent thancoalescents and as such will stay and soften a film resulting in poorperformance. As shown in FIG. 23, the Konig Hardness data disproved thisgenerally held belief. The 6% plasticizer films (X20 and X250) weresomewhat softer than other coalescents, but as seen in the MFFT dataabove, they may have been over-coalesced. 4% plasticizer films were allsimilar to the much more volatile coalesced OPV's.

Overall, the OPV evaluation showed that the inventive triblend had lowvolatility, good compatibility, and comparable dry time, gloss, andhardness and, as such, is suitable for use as an alternative in OPVapplications.

In accordance with the patent statutes, the best mode and preferredembodiments have been set forth; the scope of the invention is notlimited thereto, but rather by the scope of the attached claims.

What is claimed is:
 1. A plastisol composition, comprising: a. apolymeric dispersion; and b. a non-phthalate, high solvating plasticizertriblend comprising diethylene glycol dibenzoate present in an amount ofat least about 60 wt. %, dipropylene glycol dibenzoate present in anamount of at least about 15 wt. %, and 1,2-propylene glycol dibenzoatepresent in an amount of at least about 20 wt. %, based upon the totalweight of the triblend, wherein the Brookfield viscosity and freezingpoint of the triblend is lower than that achieved with a diethyleneglycol dibenzoate/dipropylene glycol dibenzoate diblend.
 2. Theplastisol composition as set forth in claim 1, wherein the polymer ispresent at 100 parts by weight, and wherein the plasticizer triblend ispresent at from about 1 part to about 300 parts by weight for every 100parts by weight of polymer.
 3. The plastisol composition as set forth inclaim 2, wherein the plasticizer triblend is present at about 70 partsby weight for every 100 parts by weight of polymer.
 4. The plastisolcomposition of claim 1, wherein the triblend is further blended with aconventional plasticizer comprising: phthalate esters; phosphate esters;adipates; azelates; oleates; sebacates; succinates; terephthalates;1,2-cyclohexane dicarboxylate esters; epoxy plasticizers; fatty acidesters; phenolic resins; amino resins; hydrocarbons and hydrocarbonderivatives; monobenzoates; 2,2,4-trimethyl-1,3-pentanedioldiisobutyrate; and mixtures thereof.
 5. The plastisol composition ofclaim 4, wherein the conventional plasticizer is selected from the groupconsisting of diisononyl cyclohexane-1,2-dicarboxylate, di-2-ethyl hexylterephthalate, isononyl benzoate, isodecyl benzoate, 2-ethyl hexylbenzoate and mixtures thereof.
 6. The plastisol composition of claim 1,wherein the triblend comprises 80 wt. % of a mixture of diethyleneglycol dibenzoate (DEGDB) and dipropylene glycol dibenzoate (DPGDB),wherein the ratio of DEGDB to DPGDB is about 4:1, and 20 wt. % of1,2-propylene glycol dibenzoate, based upon the total weight of thetriblend.
 7. The plastisol composition of claim 1, wherein the polymericdispersion is a PVC or acrylic-based polymer.
 8. The plastisolcomposition of claim 3, wherein the polymeric dispersion is a PVC oracrylic-based polymer.
 9. The plastisol composition of claim 4, whereinthe polymeric dispersion is a PVC or acrylic-based polymer.
 10. Theplastisol composition of claim 5, wherein the polymeric dispersion is aPVC or acrylic-based polymer.
 11. The plastisol composition of claim 6,wherein the polymeric dispersion is a PVC or acrylic-based polymer.